Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 180744
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
244 AM CDT Mon Mar 18 2024

.KEY MESSAGES...

- Another dry cold front moves through the region late tonight
  into Tuesday morning. Winds could gust into the 30 to 40 mph
  range tonight and into the 25 to 35 mph range on Tuesday.

- Accumulating snow continues to look likely from Thursday
  afternoon into Friday. Snow amounts at this time look to be 0
  to 2 inches in northeast Iowa and 1 to 4 inches elsewhere.

- From this weekend into early next week, plenty of uncertainty
  on temperatures, and precipitation timing, types, and amounts.
  Due to this stayed with the NBM for this time period.

&&

.DISCUSSION...
Issued at 244 AM CDT Mon Mar 18 2024

Today...

The combination of low level moisture and cyclonic flow aloft
this morning will keep instability clouds across the area
into the mid to late morning. As the ridge axis move through the
area during the late morning and early afternoon, skies will
quickly clear across the area. High temperatures will be in the
mid- to upper 30s. Early morning wind chills will be in the
single digits and teens. Afternoon humidities range from the
mid-20s to mid-30s. Northwest winds will gradually shift to the
west and southwest this afternoon. Wind speeds range from around
10 to 15 mph.

Tonight into Tuesday...

A cold front will move through the region late Monday night into
Tuesday. The strongest wind gusts continue to look like they
will occur tonight. Like the past couple of Canadian cold
fronts, it looks like this front will move through the region
mainly dry. If there is any precipitation at all, it would be
in the form of sprinkles and flurries north of Interstate 94.

The 18.00z HREF has a 40 to 50% probability of 40 mph or
greater wind gusts tonight along and west of the Mississippi
River. These probabilities than dramatically decrease on Tuesday
morning. Looking at the GFS and NAM BUFKIT soundings, not quite
seeing gusts quite this strong. Wondering whether these might
be coming from the CAMs. During the day, the 18.00z HREF has
30-70% chance of wind gust in the 30 mph range and up to a 20%
chance of 35 mph or greater.

With the models showing neutral to slight warm air advection at
925 mb, temperatures will likely not cool much during the day.
High temperatures on Tuesday will be in the 40s north of
Interstate 90 and around 50.

With the drier dew points being slower to advect into the area.
The 08.00z HREF have the probabilities of relative humidities
dropping below 35% at less than 15%. However, with the stronger
northwest winds over the area and the potential to mix deeper,
we will continue to monitor these relative humidities closely.

Wednesday...

The relative humidities during the afternoon will range from the
teens to lower 20s. Fortunately, the northwest winds will be in
the 10 to 20 mph range. High temperatures will be around 30
degrees north of Interstate 94 and in the lower to mid-30s
elsewhere.

Thursday afternoon into Friday...

The 18.00z models are still showing that a short wave trough
will move southeast through the region. Like the past couple of
days, it continues to look cold enough that the precipitation
will be mainly snow. The 17.12 LREF-NH continues to show that
the 10th to 90th percentiles for snow (10 to 1 ratio) of 0 to 2
inches for northeast Iowa and 1 to 4 inches across the remainder
of the area.

Upcoming Weekend into Early Next Week...

Still plenty of uncertainty on the track and timing of several
systems. The operational 18.00z GFS continues to be much further
east with its track than the operational Canadian and ECMWF.
While operational GFS is further east, the GEFS has its low as
far west as the eastern Dakotas. With so much spread in the
operational models and their ensemble members opted to continue
to stay with the NBM for temperatures and precipitation chances.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 942 PM CDT Sun Mar 17 2024

VFR conditions are forecast through the TAF period. A mid-
level stratus deck remains in place overnight tonight for most-
some clearing possible in parts of southeast Minnesota and
Northeast Iowa for a few hours tonight before another stratus
deck moves in. Clouds scatter out by midday Monday wind
increased mixing. Winds will be out of the west/northwest at 10
to 15 knots through much of the period.

&&

.FIRE WEATHER...Tuesday and Wednesday
Issued at 244 AM CDT Mon Mar 18 2024

We area continuing to monitor the relative humidity and winds
for Tuesday. It continues to look similar to Saturday where a
cold front will move through the region early in the day. The
strongest wind gusts continue to look like they will occur on
tonight. The 18.00z HREF has a 40 to 50% probability of 40 mph
or greater wind gusts on Monday night along and west of the
Mississippi River. These probabilities than dramatically
decrease on Tuesday morning. Looking at the GFS and NAM BUFKIT
soundings, not quite seeing gusts quite this strong. Wondering
whether these might be coming from the CAMs. During the day, the
18.00z HREF has 30-70% chance of wind gust in the 30 mph range
and up to a 20% chance of 35 mph or greater.

As far as dry air, the models are slower at moving the drier air
southeast into the region. This is resulting the 18.00z HREF
probabilities for relative humidities of less than 35% at less
than 15%. We will continue have to watch to see whether we
happen to mix deeper. If that did occur, the relative humidities
would drop into the mid and upper 20s and wind gusts would
likely climb into the 35 to 40 mph range.

On Wednesday, the relative humidities during the afternoon will
range from the teens to lower 20s. Fortunately, the northwest
winds will be in the 10 to 20 mph range. High temperatures will
be around 30 degrees north of Interstate 94 and in the lower to
mid-30s elsewhere.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...Boyne
AVIATION...KAA
FIRE WEATHER...Boyne


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